The influence of laser polarization variations on CPT atomic clock signals

The Coherent-Population-Trapping (CPT) vapor-cell atomic clock represents a clear break from previous vapor-cell clock technology. As such it has advantages that may result in significant frequency stability improvements. However, along with the technology´s benefits come new effects that may limit the CPT clock´s capabilities, and one such effect is laser polarization noise. Here, we present our first results looking at the response of a CPT signal to modulation of a laser´s polarization. Our results show that the CPT clock signal undergoes a splitting when the polarization modulation is rapid, suggesting that various Fourier components of a field´s stochastic polarization fluctuations will affect the CPT clock signal in qualitatively different ways.